[fajimr]

I accidentally burned through the auricap plastic cover with my soldering iron 
I can see a tiny piece of the metal inside...  just wondering what the sonic consequences are and if I need to replace it.  For the moment I have put on a couple of layers of electrical tape.

thanks in advance
jim

[mgalusha]

If you burned through more than one layer it's quite possible you shorted the cap. Check the resistance with a multimeter, being sure to discharge it first. If the resistance is not very high it's shorted. If it's shorted, throw it away. Even if you're worried I'd toss it. If used in a high voltage situation it's very possible it will fail and pass DC through to whatever is on the other side, almost certainly causing something bad to happen.

Just my $.05, Mike

[fajimr]

thanks mike- good call.  checked the resistance of both caps and there was none in the damaged cap.  looks like I have to get a new one. 

jim

[sorenj07]

You forget a very important factor to consider when dealing with metallized film caps.  These have a self-healing tendency: the metal that is causing the short might quite possibly vaporize and eliminate the short.  You lose a bit of capacitance due to this, but your cap should live.  Make sure everything is safe and fused and maybe try putting the cap across mains, or a steady high-DC supply.  If worst comes to worst, you've busted the cap and a fuse for good, if I'm right, you've saved a few dollars.  Just dab some epoxy or something over the "wound", and maybe put some tape over it for good measure. 

[JoshK]

Do you have a variac?  You could try to bring it up slowly.  I picked up a variac recently for about $60.  Extremely useful to have for any diy'er!

[fajimr]

thanks guys for the extra suggestions but just ordered one from parts connexion...  I've been working on this preamp (Aspen GK1) and want to get it singing soon.  Funny thing is that when I played it I really didn't notice that much difference in sound.

lesson learned.  price paid.

jim